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T. H. THOMAS TRAIN CONTROL DEVICE June 28, 1927.

Original Filed Marqh 1924 INV ENTOR THOMAS H.THOMAS ATTORNEY Reiaued June 28, 1927.

UNITED STATES PATENT orrlciz.

THO HA8 H. THOMAS, OF EDGEWOOD, PENNSYLVANIA, ASSIG-NOB '10 'rrm' HOUSE LIB BRAKE COMPANY, OF WILMEBDING, PENNSYLVANIA, A CORPORATION OI PENNSYLVANIA.

ample, then the speed control apparatus would fail to function as intended.

II The principal object of my invention is to provide means rative upon failure of the speed governor or reducing the speed of the train.

In the accompanying drawing: Fig. 1 is 20 a diagrammatic view of mechanism for limitin the speed of the train, in case of failure of'file speed governor, in accordance with my'invention; Fig. 2 a section on the line 22 of Fig. 1; Fig. 3 a section on the line 2 3-3 of Fig. 1; Fig. 4 a section on the line 4+4 of Fig. 1; Fig.5 a section on the line 55 of Fig. 1; and Fig. 6 a developed view of the contact segments of the contact drums shown in Fig. 1.

so As shown in Fig. 1, the shaft 1 is operativel connected so as to rotate when the spec governor (not shown) of the s ed control apparatus rotates, while the s aft 2 is o ratively, connected so as to rotate 36 when t e locomotive axle, or other rotating part of the locomotive, rotates.

' Applied to the shaft 1 is a drum 3 of insnlating material and carried by said drum are continuous contact rings 4, 5, and 6,.and

l0 alined contact segments 7,- 8, and 9, the contact'rings 4, 5, and 6 being electrically connected to the respective contact segments 7, 8, and 9. i

Applied to shaft 2 is a drum 10 of insulat- 4 ing material and carried by said drum are continuous contact rings 11, 12, and 13, and alined contact segments 14, 15, and 16, which are electrically connected to the respective contact rin 11, 12, and 13.

Contact ngers 17 18, and 19 engage the respective contact rings 4, 5, and 6 and con- .35 is unseated, so that flui 'raanr-con'rnor. DEVICE.

dated January 19, 1926, Serial No. 701,377, flied larch 84, 1994. Application for reissue filed March 7, 1927. Serial No. 178,504.

tact finger 20 engages the contact segments 7, 8, and 9. Contact fingers 21, 22 and 23 engage the contact rings 11, 12, and 13 and contact finger 24 engages. the contact segments 14, 15, and 16. The contact-fin are 17 18, and 19 are electrically conne to the respective contact fin ers 21, 22, and 23 and the contact finger 20 isconnected to. one terminal of an electro-magnet 25. The contact finger 24 is connected to a source of cur- 'rent'26 which is in circuit with the magsource of fluid under'pressure, such as the reservoir 32 and fluid equalizes' from chamber through a restricted port 33 into piston chamber 28. With the fluid pressures equalized on opposite sides of piston 29 the spring 34 maintains the piston 29 in re ease position, as shown in Fig. 1.

The magnet 25' controls a valve 35 and when the magnet is deener ized, the valve will be vented from piston chamber 28.

- The shaft'l which rotates when the s governor shaft rotates and the shaft 2 w 'ch under pressure rotates when the locomotive axle rotates are so geared that both shafts rotate at the same speed and the contact drums 3 and 10 are so positioned that the contact finger 20 will successively engage the contact segments 9, 8, and 7 at the same time that the contact finger 24 successively engages the contact segaments 16, 15, and 14 when the drums 8 an 10 are rotated at the same speed and in the same direction.

Taking the position shown in Fig. 1, the contact finger 20 engages the contact 52%; ment 9, while contact finger 24 en es segment 16 and by reference to ig. 6, it will be clear that a circuit is completed through the mag-net 25 and the source of current 26 as f0 lows: from contact finger 8 and 15. The circuit is now tree from finger 20, through contact segment 8, rmg 5,

ring 12, and segment 15, to finger 24. In

the same way, when the fingers 20 and 24 pass to the segments 7 and 14, the circuit is completed from finger 20, through contact segment 7, ring 4, ring 11, and segment 14 to finger 24.

It will thus be seen that so long as the shafts 1 and 2 and the drums 3 and 10 rotate in synchronism, the circuit of the magnet 25 will be maintained and said magnet will remain energized, and so long as the magnet 25 is energized, the .valve is held seated and no action takes place.

' If, however, the shaft 1 should cease rotating, while the shaft 2, rotating with the locomotive axle, continues to rotate, then as soon as the rotating drum 10 has rotated so that the contact finger 24 passes out of en gagement with the contact segment corresponding with the contact segment with which the finger 20 en ges, the magnet oncuit will be roken. or example, assume that the drum 3 ceases to rotate while the contact finger 20 engages the segment 9,

then the drum 10, continuing to rotate, causes the contact segment 16, to move out of engagement with the contact finger 24, and thus open the magnet circuit.

When the magnet 25 becomes deenergized by the opening of the. magnet circuit, the valve 35 will be unseated, so that fluid will be vented from the piston chamber 28. The piston 29 is then operated and the slide valve 31 is shifted to connect the usual train brake pipe 36 throughcavity 37 with an exhaust port 38. .Fluld under pressure is consequently vented from the brake pipe to eflect an appllcation of the brakes in the usual manner.

It is possible that the drum 3 may cease rotating when the contact finger 20 happens to bridge adjacent contact segments," and if each drum were only provided with two contact segments and two contact rings, the circuit would not be broken by the continual rotation of the drum 10, since the circuit would be maintained through either one or the other of the two contact se cuts on the drum 3, both of the segments nected to the finger 20.

For the above mason, it is ,preferable to ing conprovide three-or more contact segments on each drum, so that there will always be a segment which is not connected to the finger 20 in case the drum 3 to rotate.

2. In an electric circuit controlling mechanism, the combination with two rotating elements, each carrying a plurality of contact segments, of a, contact engagingthe contact segments of each rotating element and adapted to maintain anelectric circuit closed so long assaid elements rotate in synchronism, the circuit being opened by the continued rotation of one element upon failure of the other element to rotate.

3. In an electric circuit controlling mechanism, the combination with two rotating elements, of a plurality of contact segments movable with each element, a contact finger engaging the contact segments of each element and adapted to maintain an electric circuit closedfso lon as said elements r0- tate in nchronism, e circuit being opened upon failure of one element to rotate.

4. In an electric circuit controlling mechanism, the combination with two rotating elements, of aplurality of contact segments movable with each element, means for conloo nectmg each contact segmentof one element a contact segment of the other element,

a; contact finger engagin the contact segments of each element an adapted to maintain an electric circuit closed when said elements rotate in synchronism, the circuit be mg opened upon failure of one element to rotate.

5. In an electric circuit controlling 'device, the combination with two synchronously rotatable elements, of a plurality of contact members carried by one element, contact members carried by the other element and each electrically connected to a com onding contactmember of the firstrotatab e ele- 116 ment, and a contact finger ada ted to engage the contact members of eac rotatable element, said fingers being positioned to engage corresponding connected contact members and continuously maintain an electric 120 circuit closed, so long as, said elements rotate in synchronism.

6. In a train control apparatus, thecombination with electrically controlled means operating upon 'deener 'zation to efiect an a 5 plication of the bra es, of two rotating el ments, contact segments carried by and movable with such element, a contact finger engaging the contact segments of each rotating element and adapted to maintain the circuit of said means closed when both elements rotate in synchronism, said circuit being opened upon failure of one element to rotate.

7 In a train control apparatus, the com-- of the other element, and a contact finger for each element in circuit with said magnet and adapted to engage corresponding contact segments of each element to maintain said'circuit closed, so long as said elements rotate in synchronism.

8. In an electric circuit controlling device, the combination with two rotating elements, of a plurality of continuous contact rings carried by each element, a contact finger engaging each ring, each contact finger of one element being connected to a contact finger of the other element, contact segments carried by each element and each connected to a corresponding contact ring, and a contact finger engaging the contact segments of each element and connected to an electric circuit.

In testimony whereof I my hand.

have hereunto set THOMAS H. THOMAS. 

